Docket Number
110 MW
Sonoma County
Steam Turbine
Project Status
Operational (Geothermal)
Project Type
Application for Certification
Project Description

The Quicksilver Geothermal Project (Unit 16) is in Lake County near the Sonoma County line, in the Geysers Known Geothermal Resource Area along the ridgeline of the Mayacamas Mountains with moderately steep terrain, approximately 15 miles west of the town of Cobb. Unit 16, originally known as Pacific Gas & Electric Company’s (PG&E) Geysers Unit 16 Geothermal Project was certified by the California Energy Commission (CEC) in September 1981. Commercial operation began in October 1985.

The dry-steam geothermal plant was approved for up to 110-megawatts; however, due to reduced steam pressures, the plant supplies about 53-megawatts of base-load electricity to northern California's power grid. Major structures include a turbine building, cooling tower, electrical switchyard, and a hydrogen sulfide (H2S) abatement facility. The turbine building houses the steam turbine generator and other associated equipment required for electrical power production. The mechanical draft cooling tower dissipates heat from the power cycle. Hydrogen Sulfide (H2S) emissions are abated using a surface condenser/Stretford process which partitions the H2S into gaseous and condensate (liquid) forms.

In April 1999, the California Energy Commission granted a transfer of ownership of Quicksilver Geothermal (Unit 16), the former PG&E Geysers Unit 16 Geothermal Project to Geysers Power Company, LLC, a wholly owned subsidiary of the Calpine Corporation.

Order Rescinding Condition LL of the Commission Decision, Not in Docket, 06/22/1988, Order No. 88-0622-35j, Commission approval to rescind Condition LL requiring revegetation of the north and northeastern perimeters. 

Order Approving Amendment to Biological Resources Condition of Certification No. 3, Not in Docket, 03/29/1989, Order No. 89-0329-09a, Commission approval to modify Condition of Certification BIO-3. 

Commission Order Approving Ownership Transfer, TN 11770, 04/22/1999, Order No. 99-0414-01b, Commission approval of ownership transfer from PG&E to Geysers Power Company. 

Approval of Petition to Use Reclaimed Wastewater and Approval of Verification Changes, TN 31107, 03/12/2004, Staff approval of the use of reclaimed municipal wastewater at the six Calpine Geysers geothermal power plants as well as revision of the reporting requirements in the condition of certification verifications. 

Authorization for Calpine to Obtain Demolition Permits from Sonoma and Lake Counties for Demolition, TN 206699, 11/19/2015, Staff approval for Calpine to obtain and implement county-issued demolition permits to abate fire damage to structures at Geysers 16, 18, and 20. 

Order Approving to Replace Temporary Portable Emergency Diesel Engines with Stationary Permanent Emergency Diesel Engines, TN 226127, 12/17/2018, Order No. 18-1210-02, Commission approval to replace temporary portable emergency diesel engines with stationary permanent emergency diesel engines for the cooling tower wet-down systems to aid in fire prevention at the Quicksilver, Socrates, and Grant geothermal power plants. 

Resolution Approving (DCBO) services for fire system recommissioning activities at the Geysers facilities, TN 230277, 10/18/2019, Resolution No. 19-1014-04, Approval of Agreement 700-19-003 with NV5, Inc. for a $0 contract to provide delegate chief building official services for fire system recommissioning activities at the Geysers facilities.  

Order Approving Settlement for Fire Protection System, TN 235706, 11/19/20, Order No. 20-1116-02, Commission approval of the Settlement Agreement and changes to the conditions of certification and direct the Executive Director to execute the Settlement Agreement on behalf of the CEC. 

Attention: Non-hypertext items above will need to be requested from the Compliance Project Manager, along with the document TN number, if provided above. 

Power Plant Certification and Exemption Processes

The CEC has the exclusive authority to certify all thermal power plants 50 megawatts (MW) and larger and related facilities proposed for construction in California. The Application for Certification (AFC) process is a certified regulatory program under the California Environmental Quality Act (CEQA). As a certified regulatory program, the CEC does not prepare environmental impact reports (EIRs) in an AFC proceeding, but instead prepares environmental assessment documents that are functionally equivalent to EIRs. A certificate issued by the CEC is in lieu of any permit, certificate, or similar document otherwise required by any state, local or regional agency, or federal agency to the extent permitted by federal law, and supersedes any applicable statute, ordinance, or regulation of any state, local, or regional agency, or federal agency to the extent permitted by federal law.

Original Proceeding

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Docket Log (79-AFC-05)

Exhibit List

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Keith Winstead
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(916) 208-3849

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